1. Field of the Invention
The present invention relates to chair parts, and more particularly to a chair with height adjustable armrests and a foldable back.
2. Description of the Prior Art
Conventional chairs are inconvenient to store since the chair back occupies large space. As a result of this, a chair with a foldable back was developed on the market, such as U.S. Pat. No. 7,311,361 entitled with “apparatus for simultaneously folding seat chair back and armrest, although such a chair is quite convenient to store since the chair back and the armrests can be simultaneously folded, its structure is relatively complex, and the height of the armrest cannot be adjusted as desired.
Hence, Taiwan Patent No. 086217219, entitled with “height adjusting apparatus for chair armrest” was developed in order to overcome the above problem. This technology utilizes both ends of a spring to push the cylindrical engaging portions outwards and utilizes the engaging portions to position the chair armrest, so that if the height of the chair needs adjusting, the spring will be axially compressed in such a manner that the engaging portions axially retract to disengage from the chair armrests. Obviously, the technology that a spring cooperates with a cylindrical structure to move axially is not new, but the technology of controlling the armrest position is not limited to enabling the engaging portions to move axially to position the armrests, so that the applicant of the present invention has developed a chair with height adjustable armrests and a foldable back from the angle of changing the controlling and positioning manner and simplifying the structure used for folding the chair back.